Nine days earlier, Adam Rosales hit a clear game-tying home run that was disallowed.On Friday, he hit a drive well out to left in the eighth inning, and it proved the deciding blow in the A's 2-1 victory over the Royals. Josh Donaldson's solo shot the previous inning tied the game and ended James Shields' run of 15 scoreless innings at the Coliseum."That one did count," Rosales said, grinning. "I hit it hard enough to make sure it got out of the ballpark.""He put a good charge into it," A's starter Jarrod Parker said. "That was a no-doubter."Rosales hit a two-out drive off a railing in left in Cleveland on May 8, but umpires declined, after reviewing replays, to reverse their call that the ball had stayed in play. Major League Baseball acknowledged the next day that was an incorrect decision.A's manager Bob Melvin said he thought Shields made just two mistakes over the middle all night: the balls Donaldson and Rosales hit out. Donaldson extended his hitting streak to a career-high-tying six games, and he is batting .384 over his past 24 games.Parker put together his best start of season, allowing four hits, two walks and one run in a season-high seven innings. Parker, whose ERA was over 7.00 at the start of the month, said he feels he has been piecing things together, and his fastball command his past few times out has been a particular key.With Friday's news that top starter Brett Anderson will be out for more than a month with a stress fracture in his right foot, a return to form by Parker, the No. 2 starter, would be even more welcome."Obviously, it's a big blow, but we've got to keep pitching, doing our thing," Parker said of Anderson's injury.Initially, the A's had Anderson penciled in for a Friday return date from the disabled list, but instead the team announced that Anderson's right foot will be immobilized for four weeks. He will be re-evaluated then, but even if the foot has healed, Anderson will have to go through rehab and build up his innings, so he will be out at least until the end of June.